PPM?

[PharCyde]

I always forget this
does 1mg/L = 1ppm OR 10ppm?
Cheers

[Rex Grigg]

1 ppm

[Wasserpest]

1 ppm = 1 part per million

1 liter = 1000 grams = 1,000,000 milligrams

Therefore, 1 milligram per liter equals 1 part per million.

... the metrical system... too logical to be understood...

:mrgreen:

[Doomer]

It's easy to understand if you've never been corrupted by that "other" system.

[Wasserpest]

I know :roll: I had/wanted to get used to the "other" system, and even after 7 years I am lost in between Celcius and Fahrenheit :?

[mario]

Same here Wasserpest. I've been in the States for 7 years and I only know 0C=32F and 37C=98F. Everything in between I just have to guess.

[Wasserpest]

The two marks I remember are

68 = 20 = too cold for fishies
86 = 30 = too warm for fishies

I am glad I don't have to deal with Kelvin as well :lol:

[Saluki]

Originally Posted by Wasserpest

1 ppm = 1 part per million

1 liter = 1000 grams = 1,000,000 milligrams

Therefore, 1 milligram per liter equals 1 part per million.

... the metrical system... too logical to be understood...

:mrgreen:

In the interest of accuracy, I want to point out that this is fairly true in the limited case of a dillute aqueous solution, which we have in an aquarium. In general, 1 ppm is not necessarily equal to 1 kg/liter. It all depends on what solvent/solute you are talking about. Even if water is your solvent, it will not weigh 1000 kg/liter in concentrated solutions.

So, yes, in fishkeeping terms, it is accurate enough, but it is not always accurate.

[m.lemay]

Water weighs 1000 grams per liter or 1 KG per liter. 1000kg is a metric ton. [/quote]

[Wasserpest]

Originally Posted by Saluki

Even if water is your solvent, it will not weigh 1000 kg/liter in concentrated solutions.

Not even close :lol:

You are right, a liter of mercury will weight much more than 1 kg, and for aquaristic use this equation is still close enough. Thanks for clarifying. :mrgreen:

[Saluki]

ops: Edited typo. My point is that pure water at room temperature weighs about 1000 mg/liter. If you go outside that range by either changing the temperature, or by adding other substances to the water, then the density changes, and therefore 1 ppm no longer equals 1 mg/kg.

A prime example I just thought of is a marine tank. 1 ppm would definitely not be equal to 1 mg/liter in a SW set up.

[m.lemay]

The entire metric system was based on the physical properties of Pure water.. Water freezes at 0 celcius and boils at 100. 1 ml of h2o weighs a gram and 1cubic millimeter=1ml=i gram and so on. But this only works for pure h2o. Other substances have different densities which throw off the whole lineal relationship as in the salt in salt water. 8)

[Deuce868]

I remember when I was in school all of our teachers told us we would be using the metric system by the time we got out of school. Hmmm...I think I missed the change somewhere.

[PharCyde]

Thankyou. It was late at night and i couldnt remember. I worked that out but just wanted a clarification
Cheers